Long before Oris was relaunched as "High Mech" company, there were one of
the most interesting manufacturers of pin lever movement, with a bandwidth ranging
from simple pillar constructions up to officially certified pin lever chronometers.
The Oris 158 is from the entry range, but at least offers an interesting kind of
shock protection.
The construction of this movement, which is built as a pillar construction,
is pretty standard: The high building mainspring barrel directly drives the center minute
hand and this gear drives third wheel, fourth wheel and escapement wheel. The balance
beats with 18000 A/h and can be adjusted by a long regulator arm. The hairspring key
is less precise, since the distance between the two pins is very large.
The high building mainspring barrel contains a larger mainspring, which leads to longer
power reserve and an increased precision.
movement works - here with yet wrongly inserted fourth- and escapement wheel
At "4:30", you see the U-shape of the lever bearing. A watchmaker can bend it to achive
an optimal depthing for the lever pins.
main plate
The Oris 158 has got an axial shock absorber, which protects the axle of the three-leg
balance against vertical shocks. It works with moveable cap jewels for the balance bearings.
Lateral shocks cannot be absorbed at all, and so in literature, these mechanisms are called
partial shock absorbers.
open shock absorbing mechanism
The macro photos show the bordered cap jewel of the upper escapement bearing. It is held in
position by a fork spring, whose one ending is connected to the long regulator arm.
shock absorber and open bearing
On the dial side, there's a similar mechanism: Here, a non-bordered cap jewel is held in position
by a spring with two holes, so that it can be moved up and down on axial shocks.
shock protection on dial side
At "9", you see the balance bearing with dismounted cap jewel. The cap jewel is put into the hollow on the plate
and kept in position by a spring.
dial side without shock protection
On the dial side you see the rocking bar winding mechanism, whose spring is also used as click spring.
The click mechanism is quite well made for such a simple pin lever movement.
dial side view
Technical data
Manufacturer
Oris
Caliber
158
Number of jewels
2
Escapement
pin lever
Balance
Nickel
Shock protection(s)
Oris
Balance cock direction
clockwise
Hairspring stud
fixed
Regulator type
Long regulator arm
Movement construction
Fork Escapement wheel, Fourth wheel, Third wheel, Center wheel, Mainspring barrel
Construction type
pillar construction
Bridge shape
full plate including esc.wheel,
escapement with own cock,
4 gears
